Room temperature preparation of δ-phase CsSn_(1-x)Pb_xI_3 films for hole-transport in solid-state dye-sensitized solar cells

摘要

CsSn~(1−x)Pb~(x)I~(3)films were prepared from mixed CsI, SnI~(2)and/or PbI~(2)solutions at five different Pb/Sn ratios (x = 0, 0.2, 0.5, 0.8 and 1) at room temperature. The color of the CsSn~(1−x)Pb~(x)I~(3)films varied with their Pb/Sn ratios. At a Pb/Sn ratio of 0.5, CsSn~(0.5)Pb~(0.5)I~(3)had the darkest color, whereas films at other Pb/Sn ratios displayed dark brown or yellowish colors. The XRD spectra of the as-prepared CsSn~(1−x)Pb~(x)I~(3)films matched the δ-phase (yellow-phase) nonperovskite structure quite well. Solid-state dye-sensitized solar cells (S-DSSCs) were assembled by directly dropping the mixed CsI, SnI~(2)and/or PbI~(2)solution onto TiO~(2)-coated-dye electrodes and drying them at room temperature. A CsSn~(0.5)Pb~(0.5)I~(3)based S-DSSC generated the highest efficiency (3.47%) of the five conditions (CsSn~(1−x)Pb~(x)I~(3), x = 0, 0.2, 0.5, 0.8 and 1). This is attributed to the dark color and good continuity of the CsSn~(0.5)Pb~(0.5)I~(3)film, its high shunt-resistance (10,377.10 Ω) and high incident-photon collecting efficiency of CsSn~(0.5)Pb~(0.5)I~(3)based S-DSSCs.